Perinatal outcomes after admission with COVID-19 in pregnancy: a UK national cohort study

There are few population-based studies of sufficient size and follow-up duration to have reliably assessed perinatal outcomes for pregnant women hospitalised with SARS-CoV-2 infection. The United Kingdom Obstetric Surveillance System (UKOSS) covers all 194 consultant-led UK maternity units and included all pregnant women admitted to hospital with an ongoing SARS-CoV-2 infection. Here we show that in this large national cohort comprising two years’ active surveillance over four SARS-CoV-2 variant periods and with near complete follow-up of pregnancy outcomes for 16,627 included women, severe perinatal outcomes were more common in women with moderate to severe COVID-19, during the delta dominant period and among unvaccinated women. We provide strong evidence to recommend continuous surveillance of pregnancy outcomes in future pandemics and to continue to recommend SARS-CoV-2 vaccination in pregnancy to protect both mothers and babies.


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No software was used for data collection DData cannot be shared because of confidentiality issues and potential identifiability of sensitive data as identified within the Research Ethics Committee approval.Requests to access the data can be made by contacting the National Perinatal Epidemiology Unit data access committee via general@npeu.oc.ac.uk.The estimated response time for requests is four weeks.Data sharing outside the UK or the European Union may require consultation with the UK Health Research Agency.
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The study used self-identified etnicity, as per national guidelines in the UK official statistics the following categories were used; Black/African/Caribbean/Black British, Asian/Asian British, Mixed/multiple ethnic groups, Other ethnic group and White.
The study population was women giving birth and their infants.
Prospective inclusion from all institutions in the UK with a maternity unit, participants were informed about the study Approved by the HRA NRES Committee East Midlands-Nottingham 1 (ref 12/EM/0365) and exempted from individual consent National population based cohort of infants born to pregnant women admitted to hospital with a SARS-CoV-2 infection.Information about health and sociodemographic characteristics: maternal age, maternal body mass index, employment, parity, smoking, medical conditions prior to or in pregnancy, parity, multiple pregnancy, gestation at admission, vaccination status x The source population was 1.5 mill women giving birth;16,627 women were included with a positive SARS-COV-2 test; 16,386 had a known pregnancy outcome; 16,351 infants were born.
The study sample size depended on disease incidence, and no formal power calculations were performed.
Women with unknown birth outcome (241 women).Pregnancy loss (319 women) was excluded from analyses of perinatal outcomes The is a national population-based observational study, and randomization to different disease severity or dominant variants of SARS-CoV-2 was not possible This is an observational study and blinding was not relevant nor possible as the clinicians could not be blinded do disease severity and dominant variant .This is a national population-based observational study, not an experimental study, and repetition of measures were not relevant.Similar surveillance design was used in other countries, indicating that the surveillance method is valid and reproducible.

National, population-based, observational cohort study
Pregnant women admitted to hospital with a positive SARS-CoV-2 pcr test within 7 days prior to admission, during admission or up to 2 days after birth Complete reporting from 194 consultant-led maternity units, within an established reporting system Women admitted to hospital, clinical information was collected using stantardized case report forms

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Systems were established to ascertain complete reporting, the study was exempted from individual consent 1 March 2020 to 31 March 2022, follow up information about birth outcomes up to 31 Dec 2022 was retrieved until 24 April 2023.No Ecological, evolutionary & environmental sciences study designAll studies must disclose on these points even when the disclosure is negative.materials, systems and methods We require information from authors about some types of materials, experimental systems and methods used in many studies.Here, indicate whether each material, system or method listed is relevant to your study.If you are not sure if a list item applies to your research, read the appropriate section before selecting a response.